This invention relates to cathode ray tubes and, more particularly, to an arrangement for mounting cathode ray tubes in a tube enclosure or cabinet.
A variety of mounting arrangements have been employed in the past for mounting cathode ray tubes in tube enclosures and tube cabinets. A mounting arrangement is disclosed in U.S. Pat. No. 3,136,850 in which a clamping means is used at each corner of the tube to clamp the tube to the cabinet frame. A part of the clamping means rests firmly on one side against a bearing member associated with the cabinet frame and, at the other side thereof, a flange on the clamping means engages a groove between the tube cap and the tube body at each corner of the tube. The clamping means is secured by fastening means so that the clamping means firmly engages the corner groove of the tube.
Another type of mounting arrangement is disclosed in U.S. Pat. No. 3,283,072. In this mounting arrangement, a catch member comprising a generally planar body is secured at its base to the cabinet at the rounded corner locations of the tube. The planar body includes an interior opening into which a peripheral portion of the rimband extends. A tab formed integrally with the planar body is flexed into position behind the rimband. As a result of the flexure of the tab and its resilient nature, the tube is resiliently urged against the cabinet.
It is also known to utilize bracket members connected to the tube body in mounting the tube within the cabinet. In such arrangements, bracket members, having a base portion and an upstanding attachment portion affixed thereto, are supported on the tube by a metal tension band. In such arrangements, the upstanding attachment portion embodies a hole or, in some instances, a slot which is coupled with bolts or similar supportive means to the cabinet to support and mount the tube in the cabinet. One such mounting arrangement is disclosed in U.S. Pat. No. 4,210,935. According to this patent, a generally L-shaped bracket member having a base portion and an upstanding portion is positionally located at each of the corners of the tube in contact with the rimband which lies on the tube. The base portion of the bracket member is engaged by a metal tension band member extending about the tube to compressibly force the base portion of each bracket member against the rimband. The upstanding portion of each bracket member includes a slot for attaching the bracket members to the cabinet.
In one piece brackets similar to the one described immediately above, the upstanding portion has been placed on the tube so that it either is located towards the tube face or the tube back depending upon the cabinet design. It also is known to place a spacer element between the upstanding portion when it is located towards the rear of the tube but is being assembled with a cabinet that is designed for the upstanding portion being located towards the face of the tube. Such spacer elements are generally joined to the bracket by a nut and bolt or other commonly used fastening techniques.
Another technique known for mounting tubes onto cabinets is through the use of a sling arrangement. This arrangement uses a set of brackets mounted on the cabinet which hold a wire sling which is placed on the back side of the tube. The overall configuration of such tubes is such that the face or front portion has the largest cross-sectional area with the tube profile sloping towards the back of the tube in a general funnel shape. Since the sling is smaller than the size of the largest cross section of the tube, for instance, the face of the tube, it is mounted on the rear or funnel portion of the tube and pulled up tightly onto the tube under a degree of tension to hold the tube to the cabinet.
In other than sling type systems mentioned the disadvantage exists that the moment arm, the distance as measured from the top of the base portion or foot of the bracket member up to the slot or screw hole, ranges over rather large dimensions, such as in the order of from 0.4-0.6 inches. Because of this relatively large moment arm, and distance, the thicknesses of such brackets are necessarily large to support the relatively heavy larger sized tubes.
Another disadvantage with the known brackets is that the upstanding portions thereof are vulnerable to becoming bent and damaged during shipment and handling. Tubes are generally made in one location where they are assembled with the brackets and then moved to another part of the manufacturing building or shipped to another plant altogether for assembly to their cabinets. In addition, the tubes are handled as they are inserted into the cabinets for assembly thereto. Conventional brackets protrude so much that the handling and shipping of tubes can damage and bend the upstanding portions sufficiently that they need realignment or, in severe cases, replacement before installation proceeds. This is obviously time consuming and expensive.
Safety considerations require that the tube be located against the cabinet tube mask which surrounds the tube's face. If gaps exist between the tube face and mask, its possible that conducting articles could be slipped therebetween and contact components within the cabinet which bear electrical potential. Because of this consideration, the tube mounting brackets must be located within a given tolerance of positions, both radial and axial, as the tube is installed into the cabinet. Failing to stay within such tolerances creates undesirable tube/mask fit situations such as distortion, buckling, pucker, warpage, etc. of the cabinet, for instance, plastic cabinets, as the tube is installed. This in turn creates the unwanted gaps between the mask and tube face. Failing to stay within such toleranes also makes the assembly of the tube to the cabinet a more difficult and time consuming task. The vulnerability to bending and damage of the known brackets during shipment and handling aggravates these considerations. Currently, the assembler often must custom bend the upstanding portion of the brackets, use spacers such as rubber washers and apply custom torque adjustments to compensate for bent, damaged or out of tolerance brackets to provide a proper fit.
The foregoing problems are reduced or eliminated by the new bracket system as herein after described.